All domains lead to main domain, argh!

A domain on my server ( I have 4-5 or five of them), is directed to the main initial domain.
domain1 works fine
domain2 always resolves as domain1

I have changed nothing on the server in the past months, so this is seemingly coming form no where.

AS well, theg other sites on my server temporarily stopped resolving to the right domain, but now work. But, all names/passwords are broken. Before fixing the domain resolving issue by rebooting the server, all password resets seemed to be settled by domain1.

Also don't forget to check them manually in the console of your OS. Check every vhost in /etc/apache2/sites-enabled/ files for any case. I've had such a problem with a previous panel before i migrate to ISPConfig which was configured to work for one exact IP address and when I needed a little reconfiguration, it turned out to be a disaster. Also be aware that SEO optimization might break up for a week if you noticed this in less than 24 hours after the configuration broke.